Industrial Grade Truck Tie Down

The widely known fact is that the assembly of strap webbing and ratchet buckle usually called ratchet tie down but if we use cam buckle in place of ratchet buckle in the assembly we have cam buckle tie down, it's as simple as that. Due the low strength of the cam buckle, we usually see these cam buckle tie downs being used on pick up trucks, 1'' cams are all over the place while 2'' cams are being used in box trucks. Compare to cam buckle the ratchets are stronger and more widely used, the available sizes of ratchets are 1'',2'',3'' and 4'', and the ratchet buckle generally has higher working load limit than the cam buckle, they have working load limit of 3,333lbs, 5,400lbs and 5,400lbs respectively, these assemblies have design factor of 3:1, thus the minimum breaking strength is 10,000lbs, 16,200lbs and 16,200lbs respectively.

Of course what we discussed above is mainly for flatbed trucks and some other kind of vehicles, there are another kind of ratchet straps for semi trailers, ratchet e track tie downs , these tie down equipment will be used with E Tracks installed inside the semi trailer. It is estimated that 80% trucks are box trucks, and the e track tie down system is just for box trucks , so e track straps are most popular tie down straps. The e track straps usually have working load limit of 1000lbs, which is only 30% of the 2'' flatbed tie downs, and the breaking strength is only 3,000lbs based on design factor 3:1. the low working load limit of e track straps stems from box truck wall provides support for the loads inside the truck, come to think of it, the loads won't fall off the bed, not going to roll over, it's much safer than the cargo out there on the flatbeds, therefore low strength tie downs can be used to secure the loads.

In first paragraph we talked about design factor of ratchet tie downs, which is 3:1, so the working load limit is 1/3 of maximum breaking strength for ratchet straps, in the mean time the design factor of grade 70 tie down chains is 4:1, so the chains can support heavier load, and are more resistance to abuse, such as high/low temperature, moisture, while tie down straps usually only work well under normal condition. Nylon and polyester webbing are used in making tie down webbing, for different applications people will choose different material accordingly. Polyester webbing is almost perfect for tying down logs while nylon webbing is for small and light cargo. Elongation, tensile strength, abrasion and environment, these have to be taken into consideration when making tie down strap. When making tie down strap , manufacturer has to follow the recommendation of breaking strength and elongation requirements, when it comes to abrasion and environment, there are much more variations to be considered.

Rudy Young